Thread: nakayama maruka vs Uchigumori?

That Ozuku Asagi looks mighty mighty nice

I own a Ohzuku Kiita *adore*

Check this guy out - 330mate.com. He sells a ton of stones out of Japan for the purpose of sharpening chisels and planes, knives and swords. I recently bought 2 damascus chefs knives from him off of ebay. They were shipped in decent time, in good condition and as described. His communication is a bit poor, but his products are good.

Here is a link to his ebay store:

Shop eBay Canada Store - Japanese tools whetstone for sword:: Hi class, Yamawaku

Here is a link to his website:

天然ç¥çŸ³ æ„›åª›ã€€ä¼Šè±«éŠ˜ç¥ ã‚�ã�Œå›½åˆ�ã�®å¤©ç„¶ç¥çŸ³

Now, his website is quite difficult to understand becasue it in Japanese for the most part. But, what I did was use Google Translate to figure things out on his site.
Google Translate

Anyway, I thought I would share. I hope this can help you out.

Originally Posted by SharpMan

Hi Mike, my blade isn't A2. That I do know. My blades
have been hardened to 62,63 Rc or so.

What difference does the hardness of steel make in
sharpening? Harder steel, harder hone necessary?

The hardness of steel can span the hardness of common natural minerals.
Depending on how the steel was annealed and tempered
R62+ can be too hard for quartz rich hones. Coticule hones
have garnets as the cutting component. Garnets can scratch
quartz and can scratch hardened steel better than quartz.

Very hard steel is also brittle and reacts to sharpening in unexpected ways.

I do not know what the cutting mineral in J-nats is.

The hardness of hones is often a feeling for how the hone releases
its cutting minerals. i.e. how hard the matrix is that holds the cutting
minerals.

Originally Posted by SharpMan

Hi Mike, my blade isn't A2. That I do know. My blades
have been hardened to 62,63 Rc or so.

What difference does the hardness of steel make in
sharpening? Harder steel, harder hone necessary?

That sounds hard for vintage English and American tools. I may be way off there, 60 would surprise me.

Something that I do not see enough of are Scandinavian. My general impression is these were made harder than english_ish stuff. (unsure)True?

One basic matching steel/stone maxim I have always read is hard steel; soft stone. Soft steel; hard stone. I wouldn't take that to the extreme. I guess it is related to Nify's point about binder and abrasive loosing.

Originally Posted by kevint

That sounds hard for vintage English and American tools. I may be way off there, 60 would surprise me.

Something that I do not see enough of are Scandinavian. My general impression is these were made harder than english_ish stuff. (unsure)True?

One basic matching steel/stone maxim I have always read is hard steel; soft stone. Soft steel; hard stone. I wouldn't take that to the extreme. I guess it is related to Nify's point about binder and abrasive loosing.

That makes total sense to me Kevin. Maybe that is why the Holy Grail of hones is a superman stone that is hard a hell, cuts wicked fast and finishes super fine. I do think there are hones like that out there but most of us will never see them. Most of us will at least find functional compromises that are really pretty good in there own right and will make us satisfied.

I *believe* the hard steel - soft stone corelation refers not to the cutting agent itself, but to the binder and it refers much more to natural stones than synthetics.

If you have a very hard steel it will be reluctant to be abraded.
Therefore you have to either increase the pressure or the speed of the abrasive action.
Or you will have to increase the amount of cutting particles.

If a stone is bond soft, it will release many particles during the sharpening process, making the cutting process easyer.
That´s why softer stones propably will cut faster with harder steels,
than harder stones do

There are very few minerals that actually are softer or not significantly harder than 65HRC steel.
Not all of them are able to cut all the carbides in steel,
but this would be useless, anyway, as they will break out during use

Regardless of what I may have said in the past about wood handtoolers needing, using super sharp edges, my razors are still the sharpest things I use.

Perhaps that has as much to do with the very low angle as ultimate edge dimension. And sometimes such a fine edge is not needed. Yet, there is nothing that I have found to suggest that a razor requires something more, finer or higher quality than what a hand planning, joining cabinet maker may need. After all both can be done at 8k with excellent results. Going up and up in finer grit just makes things more excellent.

I would love to experience less compromise, but i need to up my skills before i can honestly tell myself I deserve better

Originally Posted by Lesslemming

I *believe* the hard steel - soft stone corelation refers not to the cutting agent itself, but to the binder and it refers much more to natural stones than synthetics.

If you have a very hard steel it will be reluctant to be abraded.
Therefore you have to either increase the pressure or the speed of the abrasive action.
Or you will have to increase the amount of cutting particles.

If a stone is bond soft, it will release many particles during the sharpening process, making the cutting process easyer.
That´s why softer stones propably will cut faster with harder steels,
than harder stones do

There are very few minerals that actually are softer or not significantly harder than 65HRC steel.
Not all of them are able to cut all the carbides in steel,
but this would be useless, anyway, as they will break out during use

This is an old thread, but I thought I would add to it with some pertinent info since the participants didn't seem to quite understand the hard steel/soft stone, soft steel/hard stone reasoning. Here goes.

When a stone is cutting very soft steel, the abrasive particles aren't being worn down much, nor very rapidly, so there's no need for them to shed early and often. They can remain in place and still continue to cut at a decent speed. The softer steel also has a higher coefficient of friction with the abrasive, which will tend to pull particles of abrasive from a stone faster than when sharpening a harder steel. (If you have done much reading or talking to any Japanese blacksmiths you will have heard more than a few say that they don't need nagura for their stones as their steel is made with wrought iron cladding - which is very soft and will rapidly pull abrasive particles - or slurry - from most stones). Harder stone of course has a more tenacious grip on the abrasive particles contained within. For this reason, using a harder stone is generally better when sharpening softer steel.

Conversely, when a stone is cutting harder steel, the coefficient of friction between steel and stone is lower (ever felt a stone "skate" over very hard steel almost like it's on ice?), and the abrasive particles tend to dull much more quickly. This makes it important that the particles be released quickly and often so the dull ones get out of the way and let the sharper ones go to work. So for very hard steels a softer stone is better, that way it will rapidly release worn abrasive particles once they are too dull to cut efficiently.

Hopefully that makes things very clear to all.

Thanks Eric for resurrecting this old thread and for your response to it.

As a relatively new honer of razors,that is hopelessly addicted to natural stones, I have been reading allot of old posts on the subject.
I find it fascinating to see how the discussions have changed as the knowledge and experience grows year after year.

I really had no idea that I would be studying so much about the ancient art of honing just because I decided to start shaving with straight razors.
Now, stones and steel seem to dominate my thoughts.